feat: add --wait-until flag to open command and change default to domcontentloaded

[go-to-the-future]

Summary

• Add --wait-until <strategy> flag to the open command (load, domcontentloaded, networkidle)
• Also configurable via AGENT_BROWSER_WAIT_UNTIL environment variable
• Change the default waitUntil from load to domcontentloaded in handleNavigate, aligning it with handleTabNew which already uses domcontentloaded

Motivation

The load event waits for all resources (images, stylesheets, iframes, third-party scripts) to finish loading. On modern SPAs that depend on external auth providers, analytics, or other async resources, this frequently causes navigation timeouts — especially problematic for AI agent workflows where a timeout wastes an entire agent turn.

domcontentloaded fires when the HTML is parsed and the DOM is ready, which is sufficient for most interactions. Agent workflows already follow a navigate → snapshot → interact pattern, so waiting for full load provides no additional value.

See also: Playwright docs recommend using lighter waitUntil strategies combined with element-based assertions for SPA testing.

Changes

File	Change
cli/src/flags.rs	Add wait_until: Option<String> field, --wait-until flag parsing, clean_args support, env var AGENT_BROWSER_WAIT_UNTIL, and tests
cli/src/commands.rs	Pass flags.wait_until as waitUntil in the navigate JSON command, add default_flags() field, and 4 new tests
cli/src/output.rs	Document --wait-until in open help, global options, and environment variables
src/actions.ts	Change default: command.waitUntil ?? 'load' → command.waitUntil ?? 'domcontentloaded'

Usage

# Use domcontentloaded (new default — no flag needed)
agent-browser open https://example.com

# Explicitly wait for all resources
agent-browser open https://example.com --wait-until load

# Wait for network to settle
agent-browser open https://example.com --wait-until networkidle

# Set via environment variable
AGENT_BROWSER_WAIT_UNTIL=networkidle agent-browser open https://example.com

Closes #479

[vercel]

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